XML 49 R61.htm IDEA: XBRL DOCUMENT v2.4.0.8
Financial Instruments - Additional Information (Detail) (USD $)
In Millions, unless otherwise specified
12 Months Ended
Dec. 31, 2013
Dec. 31, 2012
Derivative Instruments And Hedging Activities Disclosure [Abstract]    
Corporate and municipal bonds $ 29.0 $ 28.2
Maturity dates of bonds, start date 2014-02  
Maturity dates of bonds, end date 2018-09